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  <script>
    // num.toFixed()
    // 作用：四舍五入，保留小数位数。
    const num = 10.929
    const res = num.toFixed(2)  // 注意，返回的是string
    console.log(res)

    // 如果不传参数, 四舍五入为整数形式的字符串
    const res2 = num.toFixed()
    console.log(res2)
  </script>
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